Background: Digital technology is increasingly being used in healthcare delivery, and can potentially improve access to psychological services. “Technology-based interventions” (TBIs) are a form of self-guided psychological treatment delivered by digital technology, such as computer programs, websites, or smartphones. Little is known about how these work, and high drop-out rates raise a pressing need to understand user engagement. The therapeutic alliance concerns the level of collaboration in therapy, and is strongly linked to face-to-face treatment’s effectiveness. The validity of therapeutic alliance is uncertain in TBIs, but it may contribute towards an understanding of user engagement.

Objective: To explore the nature of the therapeutic alliance in the context of technology-based interventions (TBIs) for mental health problems.

Methods: A systematic review was undertaken, which included qualitative, quantitative and mixed methods research. 13 papers were analysed using a best-fit framework synthesis approach. A qualitative study was also conducted, using topic-guided interviews to explore 13 participants’ experiences regarding their interaction and engagement with TBIs. Thematic analysis was used to analyse the data.

Results: The user-TBI alliance is largely comprised of similar dimensions to the alliance in face-to-face therapy. There are also some new dimensions which specifically apply to TBIs: interactivity (personalising a TBI), and availability (flexible access to treatment). The user-TBI alliance may not be directly associated with outcomes, but it does appear to be related to user engagement.

Conclusions: TBI users can experience a therapeutic alliance with the digital technology, especially if the TBI is sufficiently personalised. The terminology of a “relationship” with digital technology is generally unacceptable to TBI users, which will pose challenges when attempting to adapt or design alliance measures that take account of the unique TBI context.